dendrite/federationapi/routing/events.go
2022-10-11 10:48:36 +01:00

107 lines
2.9 KiB
Go

// Copyright 2017 New Vector Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package routing
import (
"context"
"encoding/json"
"net/http"
"time"
"github.com/matrix-org/dendrite/clientapi/jsonerror"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/util"
)
// GetEvent returns the requested event
func GetEvent(
ctx context.Context,
request *gomatrixserverlib.FederationRequest,
rsAPI api.FederationRoomserverAPI,
eventID string,
origin gomatrixserverlib.ServerName,
) util.JSONResponse {
err := allowedToSeeEvent(ctx, request.Origin(), rsAPI, eventID)
if err != nil {
return *err
}
event, err := fetchEvent(ctx, rsAPI, eventID)
if err != nil {
return *err
}
return util.JSONResponse{Code: http.StatusOK, JSON: gomatrixserverlib.Transaction{
Origin: origin,
OriginServerTS: gomatrixserverlib.AsTimestamp(time.Now()),
PDUs: []json.RawMessage{
event.JSON(),
},
}}
}
// allowedToSeeEvent returns no error if the server is allowed to see this event,
// otherwise it returns an error response which can be sent to the client.
func allowedToSeeEvent(
ctx context.Context,
origin gomatrixserverlib.ServerName,
rsAPI api.FederationRoomserverAPI,
eventID string,
) *util.JSONResponse {
var authResponse api.QueryServerAllowedToSeeEventResponse
err := rsAPI.QueryServerAllowedToSeeEvent(
ctx,
&api.QueryServerAllowedToSeeEventRequest{
EventID: eventID,
ServerName: origin,
},
&authResponse,
)
if err != nil {
resErr := util.ErrorResponse(err)
return &resErr
}
if !authResponse.AllowedToSeeEvent {
resErr := util.MessageResponse(http.StatusForbidden, "server not allowed to see event")
return &resErr
}
return nil
}
// fetchEvent fetches the event without auth checks. Returns an error if the event cannot be found.
func fetchEvent(ctx context.Context, rsAPI api.FederationRoomserverAPI, eventID string) (*gomatrixserverlib.Event, *util.JSONResponse) {
var eventsResponse api.QueryEventsByIDResponse
err := rsAPI.QueryEventsByID(
ctx,
&api.QueryEventsByIDRequest{EventIDs: []string{eventID}},
&eventsResponse,
)
if err != nil {
resErr := util.ErrorResponse(err)
return nil, &resErr
}
if len(eventsResponse.Events) == 0 {
return nil, &util.JSONResponse{
Code: http.StatusNotFound,
JSON: jsonerror.NotFound("Event not found"),
}
}
return eventsResponse.Events[0].Event, nil
}